The present invention applies to a communication network in which data can be transmitted from a sender to a receiver via a number of intermediate network nodes. Data can be transmitted via different routes, each comprising one or more of the intermediate network nodes. A direct path between two adjacent nodes is referred to as a link. Depending on which communication links are used for a communication flow different transmission routes (or paths) through the network from the sender to the receiver can be distinguished.
It is important in any such communication system to optimize the selection of the routes to utilize the resources as efficiently as possible.
In existing routing solutions a route selection is typically based on assigning a cost value, or metric, to each communication route, that is, a route metric. The route metric is generally determined as the sum of the metric values for all links, or hops, in the route. Typically, but not necessarily each node determines link metric values for its own links and the values are distributed to other nodes using routing protocols. The best route is typically selected to be the route that has the best route metric.
This prior art solution has several problems. One is that the metric assigned to a route may have an uncertainty. The metric may be determined based on the estimation of link properties that may be subject to estimation errors. It may also take some time before a metric can be considered when making a routing decision. This may be due to the fact that certain changes, for example, in link properties, take some time before they are measured in the estimation process and thus influence an associated metric. Also, it may take some time for a metric to be distributed to a function which uses this metric for a routing decision.
The prior art solution described above also does not take into account the fact that the route metric is a dynamic parameter, which changes over time, for example as the load in the network changes.